Lint CI and pre-commit enforce two different formatters (black vs ruff format)

Hi — I'm looking at contributing and ran into this before I could open a PR, so I'd rather ask than guess which way you'd want it fixed.

Symptom

black --check . fails on a clean checkout of main (4b52398), so the Lint workflow is red on every PR regardless of what the PR changes.

$ pip install black==24.10.0 ruff==0.7.1    # the versions lint.yml pins
$ black --check .
13 files would be reformatted, 371 files would be left unchanged.

ruff check passes cleanly — it's only the format check that fails.

Cause

The two formatters disagree, and each rejects the other's output:

• .pre-commit-config.yaml runs ruff-format (ruff v0.7.1)
• .github/workflows/lint.yml runs black --check . (black 24.10.0)

Taking src/rb-lib/rb/lib/utils.py and formatting it each way:

$ ruff format a.py && black --check a.py
1 file would be reformatted.

$ black b.py && ruff format --check b.py
Would reformat: b.py

The divergence is how each wraps assert cond, "long message" — ruff 0.7 implements the style black adopted later in preview:

# ruff format
    assert issubclass(input_type_hint, FileInput), (
        f"For key {key}, the input type is InputType.FILE, ..."
    )

# black 24.10
    assert issubclass(
        input_type_hint, FileInput
    ), f"For key {key}, the input type is InputType.FILE, ..."

Repo-wide: ruff format --check . reports 64 files, black --check . reports 13.

Why it matters for contributors

Anyone who installs pre-commit as configured gets their commit auto-formatted by ruff into a shape the Lint job then rejects.

The question

Which formatter do you want to keep?

I'm happy to do the work either direction, in two commits so the reviewable part stays small:

1. the config change — a few lines in lint.yml and/or .pre-commit-config.yaml, plus a [tool.ruff] block in the root pyproject.toml pinning line-length and target-version so the two can't drift apart again
2. the mechanical reformat pass

Two smaller things I noticed while in there — happy to fold in or leave alone:

• lint.yml uses Python 3.11 while test.yml uses 3.12
• the root pyproject.toml has no [tool.ruff] section, so ruff check runs its default rule set only (E4/E7/E9/F)

Whichever direction you pick, the reformat commit will conflict with any long-lived branch, so I'm glad to time it for whenever is least disruptive.

Start with .github/workflows/lint.yml, .pre-commit-config.yaml, and the root pyproject.toml to compare the formatter commands and available configuration. Run the reported black and ruff format checks, then confirm the chosen formatter and scope with maintainers. Done means pre-commit and the Lint workflow enforce the same formatting and pass on the repository.